Sheet insulation



Oct. 8, 1929. w. c. FURNAS ET AL SHEET INSULATION Filed 001;. 25, 1924 i Patented Oct. 8, 1929 UNITED STATES rArsn'r OFFICE WILLIAM C. FURNAS AND EDWARD C. RUSCH, 01' WEST ALLIS. WISCONSIN, ASSIGNORB TO ALLIS-CHALMERS MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A

CORPORATION OF DELAWARE SHEET INSULATION Application filed October 25, 1924. Serial No. 745,754.

This invention relates in general to the production of laminated sheet material, and more particularly to insulating sheet material such as is adapted for electrical insulation purposes, and to apparatus for and a process of fabricating sheet material of this general class.

Laminated sheet material, especially of the type which is relatively flexible, has many uses in the art; and insulating sheet material of the required dielectric strength is espeially useful for the purpose of insulating nductors of dynamo-electric machines and other induction apparatus; and the present invention is of special utility in the fabrication of a product of this type, and particularly so where sheet or flake mica is a dielectric constituent of the laminated and, built-up fabric.

In the production of laminated sheet material including an originally fluent binder,

especially sheet material particularly adapted for insulating purposes, in accordance with prior art processes and apparatus, there has been considerable difliculty in obtaining uniform thickness and strength of the final product. This difliculty arises to a considerable extent from the unsatisfactory manner in which the fluent binder is applied to the laminae, this fluent binder being ordinarily applied to relatively segregated portions and a subsequent more or less eflective smoothing operation being relied upon for distributing the binder. As a result of these processes and apparatus for applying the binder, the final laminated sheet product is liable to be more or less non-uniform or spotty, as to thickness of the layer of binder and the laminated sheet, and consequently the mechanical and dielectric strength of the final sheet product. Another objection to the PIQXlHCtS of these prior art processes, wherein there is great liability to unevenness of the binder film or layer, and especially in connection with the production of electrically insulating sheet material, where the dielectric strength of the sheet is only that of its weakest portion, this occurring ordinarily where the thickness of-the insulating material is a m1n1mum,1s that wlth an excess of binder material in any portions, this excess, in addition to the waste ofmaterial involved, causes unnecessary increase in the bulk of the final sheet product and also greatly decreases its flexibility. This decrease in flexibility is an undesirable feature especially where the material is primarily for the purpose of in-.

bulk and decreasing the flexibility of the film product. .These undesirable characteristics of the processes, apparatus and final products of the prior art are eliminated when the sheet material is produced in accordance with features of the present invention.

In general accordance with this invention, laminated sheet material may be fabricated by a process wherein the laminated materials are laid in an extremely smooth condition and the binding material is disposed between adjacent laminae in the form of a film or coating of uniform thickness, the process and apparatus including a special feature and. means for insuring this uniform film of binding material and the removal of any excess binding material originally placed on the laminae and avoiding any appreciable undulation or creases in the laminae of the final product. A general resultant effect of the use of the process of and apparatus of this invention is the possibility of producing extremely thin laminated sheet material of great uniformity in thickness and great flexibility, while at the same time possessing uniformly great mechanical strength and also dielectric strength, where the material is intended forilse for electrical insulating purposes.

Advantages to be derived from the present invention are particularly apparent in connection with laminated sheet material especially adapted for use as electrical insu 100 lating material of high dielectric strength, such as the laminated material known to the trade as sheet mica. The use of the invention in the production of this material greatly reduces the cost and improves the quality of the product, and further, it greatly improves the working conditions of employees engaged in the manufactureof the material while per mitting the --use of relatively inexpensive binder constituents. Certain of the advantages to be derived through the present invention are due to features of design and construction of the apparatus which facilitate and insure the economical production of laminated sheet material of improved quality, these features of design and construction relating to both essential operations performed and to refinements which insure the continu ous economical and efiicient operation of the r'atus for .producing laminated sheet material.

A further object of this invention is the provision of an improved processand apparatus for producing laminated sheet material wherein an originally fluent binder is utilized between laminae of the material.

A further object of this invention is the provision of an improved process and apparatus for producing laminated sheet material wherein a layer of mica flakes and an originally fluent binder therefor are utilized as constituents of the laminated structure.-

A further object of this invention is the provision of apparatus of improved design and construction for producing laminated sheet material and embodying improved facilities for depositing and uniformly spreading an originally fluent binder, and for smoothing the laminae of the completed structure and drying the same in an eflicient and economical manner, and for maintaining the feed of the constituent laminae and thefinished product so as to insure the economical continuous operation of the apparatus.

These and other objects and advantages relating to the process and apparatus are attained by the present invention, various novel features of which will be apparent from the description and drawings herein, disclosing an embodiment of the invention, and will be more specifically pointed out in the claims.

In the accompanying drawings:

Fig. 1 is a plan view, with parts broken away, of apparatus for producing sheet insulating material in accordance with the present invention.

Fig. 2 is a view in elevation of the apparatus shown in Fig. 1, parts being broken away to show features of interior construction.

. Figs. 3, 4 and 5 are detail views of parts of the apparatus shown in Figs. 1 and 2.

As disclosed in the drawings, a frame 1 is made up of spaced and connected side pieces 2 and supports or legs 3 therefor. An endless flexible belt or conveyer 4, constituting a movable table, is carried uponrolls 5 and 5 at the ends of the machine and is suitably'supported at intermediate points, this endless of sheet fabric 12, such as tissue paper, is

carried by brackets 13 at the under side of the side pieces 2 of the frame. During operation .of the apparatus, this sheet material is fed over the roll 5 and along the upper side of the traveling conveyer. The open sides of the machine are preferably closed by plates 14 provided at suitable ,points with openings having removable closures.

The paper or other sheet material unrolled from the roll- 12 and passing over the roll 5, is laid on the traveling conveyer as indicated at 15. As the paper travels toward the right, fragments or flakes of sheet insulating material, such as sheet or flake mica, arelaid on the paper in such a manner asto entirely cover all portions of the paper, the edges of the flakes or sheets of mica being overlappedto insure that all portions of the paper are covered, thus forming a layer of mica sheet, this layer of mica being indicated at 16. As

the paper with the mica sheets deposited thereon in overlapping relation moves toward the right, an insulating bond or binder is deposited on the upper side of the layer of mica sheets, the idea being to so dispense the insulating bond having a considerable degree of fluency, as to provide a uniform covering of insulating binding material over all portions of the upper surfaceof the mica sheets, with such excess of such binding material as will permit a portion thereof to pass between the overlapping, edges of the flakes and to the opposite side thereof, so that there will be a uniform binding efi'ect throughout the completed sheet material.

The binder-dispensing apparatus includes a reservoir 18 supported in position, as on a raised frame-work 17, and a flexible conduit comprising a bent or angled section 19 c0mmunicating with the reservoir and preferably provided with a bent section 20 flexibly connected to the conduit section 19 in a fluid-tight manner at a point intermediate the edges of the conveyer, and having at its lower ends oppositely extending branches 201 and 202, each of the latter bemg provided with a don ble dispensing nozzle 21, the nozzle portions IOC being spaced and one in advance of'the other in the general direction of travel of the laminated fabric. The adjacent ends of the conduit sections 19 and 20 communicate with a T or L-shaped section 23, the connection between the section 19 and the section 23 constituting a swivel and being flexible to the extent that the section 23 with the attached section 20 may rotate about the axis of the section 19 to the extent required to permit each of the nozzles to effectively cover substantially one half of the full. width of the paper and mica flakes as they pass beneath the nozzles, while maintaining fluid-tight relation between the several conduit sections. The sectional conduit made up of the parts 19, 20, 23 is carried by a transverse supporting element of the built-up frame-work 17.

A supporting shelf 24 is provided on the framework 17, and a bar 25 is pivotally mounted at the under side of this shelf 24 and is formed with a pair of forked arms 26 at its forward end, these arms being of sufficient length and disposed so as to be in substantial engagement with opposite sides of the depending portion of the conduit section 20. A head or block 27 is rigidly mounted upon the under side of thG'PIVOtGd element 25 and carries a transverse bar 28 which is slidable in bearings 29 mounted upon the side walls of the frame 17. A pin 30 carried by the bar 28 is disposed in an eccentric cam slot 31 in the upper side of the rotatable cam disk 32 carried by the vertical shaft 33. This shaft is mounted in bearings carried by supports upon the frame-work 17 or the side pieces of the frame 1 and is driven through a speed and direction changing transmission 34 and shafts 35 and 36, the latter being driven by a belt or otherwise from the shaft of the motor 8.

As will be apparent from Figs. 1 and 3,

' the traveling fabric carried thereby, and this transverse reciprocation is communicated to the conduit section 20 and the nozzles 21 carried thereby. This arrangement for oscillating or reciprocating the dispensing nozzles 21 insures the supply, through the effect of gravity with or without supplementing pressure means, and the deposit of a relatively thin coating of fluent. insulating bond over the entire exposed upper surface of the mica flakes laid upon the paper 15. By utilizing suitable known design of the nozzles and selection of a proper speed of travel of the sheet material through the apparatus, there is s'ecured "the desired uniform coating or film of insulating bond which is preferably discharged from the nozzles in the form of small drops or a fine spray, or dust where a finely divided or powdered'bond is used. The pressure on the nozzles is sufficient to obtain the desired discharge of insulating bond. An air sulating bond, this second sheet of paper being fed from a roll 40 over guiding rolls 41, 42, the latter being disposed relatively close to the upper side of the coated mica sheets' so that the second sheet of paper may readily contact with and adhere to portions of the insulating bond deposited upon the mica sheets.

As the built-up sheet fabric with its second layer of paper advances through the apparatus, it comes under the influence of a smoothing device which has the function .of removing creases or wrinkles from the two layers of paper and of spreading the fluent insulating bond thoroughly and uniformly between these layers and also the edges of the overlapped mica sheets and, further, of forcing out from between the element of the built-up sheet any excess of insulating material not actually required for the purpose of securing the desired efiective bond be tween the constituent materials. As indicated in the drawings, the smoothing device is in the form of one or more rotating brushes 45, 46 arranged transversely of the traveling fabric and rotating in such direction as to exert a brushing or smoothing effect toward the rear .of the apparatus and, likewise, toward the edges of the built-up laminated sheet. As indicated, the brush rotates in an anti-clockwise direction and brush 46 in a clockwise direction, with respect to an observation point at the intersection of the. axes of rotation of the two brushes. I

The outer, ends of tlie rotatable brushes are mounted in bearings 47 carried by the side pieces of the frame 1, and the inner ends of these brushes are carried by the bearings 48 supported directly upon or on brackets car-. ried by the frame of the apparatus. The desired rotation of the brushes is secured through the interconnection of the brushes through beveled gears adjacent the bearings 47 and a drive forthe brush 45 through beveled gears on the shaft of this brush and the vertical shaft 51, power being supplied from the shaft 36 through a bevel gearconnection.

It is preferable to supply an excess of insulating material to the traveling sheet with the'idea of facilitating the entrance of a portion of this insulating material betweenthe flakes of mica and in contact with the lower sheet' of fabric. And the effect of rotation of the brushes 45 and 46 as described hereinabove, while in intimate contact with the upper side of the laminated fabric traveling beneath the brushes, is to smooth out any, wrinkles or creases and to fully and evenly dispose the insulating bond in intimate con-' nally and held securely on the shaft with the sections '53, 53 secured together by'bolts or screws, permitting ready removal of the brush from the shaft as for cleaning purposes. The relatively soft bristles are preferably disposed in spiral rows to better secure a uniform brushing eflec't throughout the sheet.

As the smoothen ed laminated fabric advances through the apparatus and out of the influence of the brushes, it moves into an enclosure or portion 54 wherein it now rests upon a perforated portion of the traveling conveyer beneath which is disposed a heating element H carried by transverse supports mounted upon the side pieces of the frame. This heating element H may be in the form of'conduits carrying steam or an electrical heating device or the like, for heating the air in the enclosure. The length of this enclosure in the direction of travel and the degree of heat supplied are properly proportioned so that, as the laminated material emerges from the forward side of the enclosure adjacent the roll 5*, whence it is carried to a collecting roll outside of the apparatus, the laminated fabric will be quite fully dried, that is, solvent material will be removed from the insulating binder and the latter will firmly cement the overlapping edges of the mica together and the surface portions of the mica into intimate contact with the covering sheets of paper or other fabric. In case of a powdered bond, the heat softens the bond and dries the cemented sheets of the fabric. As indicated, the upper side of this enclosure is provided with a removable cover plate 56 and is preferably open at the rear and lower sides to permit the entrance of a current of air, a discharge funnel 57. being provided at the I upper side of the enclosure at the forward end thereof. The products of the heating and drying of the fabric are carried through the funnel and a discharge conduit 58 by an exhaust fan 59 driven by a motor 60.

As described, the finished product passes out of the heating and drying enclosure and onto the collecting roll, the latter being driven preferably from the shaft of the roll 5, through a friction clutch to insure at all times suflicient slippage to give the proper peripheral speed to the materialwound on a support carried at the upper side of the frame and provided with oppositely extending arms 64 secured at the ends of the shafts. The ends of these arms are, provided with slots 65 and 67, the feed roll 40 being disposed in the slots 65 and suitably secured therein. A

reserve feedroll 68 is mounted in the slot 67 in the lower arms 64, the arrangement being such that this reserve roll can readilyv be placed in position while the apparatus is in operation. Then, as the roll 40 becomes exhausted, the reserve roll 68 can, after removing a locking pin from the arm 64, be immediately swung into normal feeding position, indicated by the present position of the roll 40, and the paper on the roll 68 secured to or superposed on the end of the sheet fed from the roll 40 to the apparatus.

The method of securing the feed roll 12 at i the rear of the machine may be the same as that described in connectionwith the support for the feed roll 40, to the end that the paper or other fabric may be supplied practically continuously, thus avoiding-stoppage of the apparatus.

A rod or roller 71 is carried by one or. more pivoted arms 72, the rod or the carrying arms 7 2 being biased by a weight, spring or otherwise, so that the rod bears upon the paper fed from the roll 40. During operation, this rod 71 is held by the\paper in the position indicated in Fig. 2, against its normal bias. In case of breakage of the paper, the rod 71 is permitted to drop causing one or both of the pivoted arms 72 to actuate a switch 73 which renders operative a signal 7 4 in the circuit of the switch. Actuation of the switch 73 may have the additional function of actuating a no -voltage release to cause stoppage of the motor 8, in case an attendant is not at hand to continue the feed of the paper, thus insuring that only completed laminated material passes through the machine. a

During operation of the apparatus in a normal and intended manner, as outlined in con nection with the description of the apparatus hereinabove, laminated fabric is produced,

this fabric comprising msulatmg material, as p in the form of mica flakes, disposed between two fabric sheets and firmly cemented thereto; and the finished material is of great uniformity and generally improved characteris- I ties as to mechanical and dielectric strength;

further, the material is produced at a cost which is 'much lower than the cost of producing this laminated sheet insulating material in accordance with the apparatus and processses of the prior art. y It should be understood that it is not desired that the invention claimed be limited to the exact details of construction, embodiments and methods set forth herein, for obvious modifications therein within the sco e of theiclaims will occur to persons skilled 1n the art.

It is claimed and desired to secure by Letters Patent: v

1. In apparatus for producing laminated sheet material, the combination of a movable I conveyer, means for supplying a sheet of. fabric to said conve er, meansfor depositing binding material ma layer above said sheet of fabrlc, means for feeding a second sheet of fabric to said conveyer and su erposingsaid latter sheet upon the layer of inding mate-. rial, and means for distributing said fluent binder beneathlsaid superposed sheet, said distributing means com rising a device for stroking said superpose sheet in a direction transverse to the direction of travel of said said conveyer.

conveyer.

2. In apparatus for producing laminated sheet material, the combination of a movable conveyer, means for supplying a sheet of material to said conveyer, means for supplying binding material in a layer above said sheet.

. means for feeding a sheet of fabric to said conveyer and superposing said latter sheet upon said layer of binding material, and means for distributing said binding material between said sheets, said means comprising a device for stroking said superposed sheet in a direction having components opposite to and transverse to the direction of travel of 3. In apparatus for producing laminated sheet material, the combination of a longitudinally movable conveyer fgr said material, means for supplying fluent binding material in a layer above a lower lamination of said material, means for supplying a second lamination and superposing the same upon said layer of binding material, and means for distributing said fluent binder in the form of a uniform film between said laminations, said means comprising a device for stroking the superposed sheet from the. center thereof-in a plurality of directions having components both parallel to and transverse to the line of travel of said laminated sheet.

.4. In apparatus for producing laminated sheet material, the combination of a movable conveyer for said sheet material, and means for supplying fluent binding material in a layer above a lower sheet of said laminated material, said means comprlsmg a-source of sup ly of fluent binder, and a dispensing noz- 'zle aving a flexible conduit connection with said source of supply, and means for moving said nozzle in apath transverse to the direction of travel of said conveyer and said sheet material to substantially evenl distribute said binder over the full area 0 .the surface of the sheet material.

' 5. In apparatus for producing laminated sheet'material, the combination of a movable conveyer for said material, and means for supplying fluentbindin material in a layer above the lower sheet 0 said laminated ma- I .terial, said means comprising a source of supply of fluent binder, and a fluid supplying evice having a plurality of nozzles one in advance of another in the direction of travel of. said conveyer, a conduit connection between said source of supply and saiddistributing nozzles permitting said nozzles to travel transversely of the direction of travel of said conveyer, and means for causing said transverse travel of said nozzles.

6. In apparatus for producing laminated. sheet material, the combination of a movable conveyer for said material, means for supplying fluent binding material in a layer above a v lower'sheet of said laminated material, means for feeding a second sheet to said conveyer and superposing said latter sheet upon the layer of binding material, and means cooperative with the exterior of said superposed sheet while the latter is in original condition for distributing the fluent binding material; between the sheets of said laminated material.

7. In apparatus for producing laminated sheet material, the combination of a longitudinally traveling conveyer for said material, means for supplying fluent binding material above a lower'sheet of said laminated material, said means comprising a source of supply of fluent binder, a discharge nozzle,

and means for causing said nozzle to travel material above a lower sheet of said laminated material, said means comprising a source of supply of fluent binder, means for dispensing said binder, said dispensing means having a flexible conduit connection with said source of supply, and means for oscillating said dis, pensing means transversely of the direction of travel of said sheet material, means for feeding a sheet of fabric to and superposing the same upon said binder, and means for distributing said fluent binder between said sheets, said latter means being operative upon the exposed surface of said superposed sheet. 9. In apparatus for producing laminated sheet material, the combination of a longitudinally traveling conveyer forsaid sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, said means comprising a source of supply of fluent binder, and a dispensing nozzle having a flexible conduit connection to said source of supply, and means for oscillating said nozzle in a path transverse to the direction of travel of said conveyer and said sheet material, said operating connection comprising a driving shaft, and a cam-operated connection between said shaft and said nozzle, means for feeding a sheet of material to and superposing the same upon the layer of binding material, and means for distributing said fluent binder between the sheets of said material, said means being operative upon the exposed surface of said superposed sheet.

10. In apparatus for producin laminated eet material, the combination 0 a conveyer for said sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, means for feeding a second sheet of material to and superposing the same upon said binding material, and a rotary brushing device cooperative with and exerting pressure on said superposed sheet and adapted to distribute the binder between said sheets and produce intimate contact between said binder and said superposed sheet and to remove through the edges of said sheet material any excess of said binder.

11. In apparatus for producing laminated sheet material, the combination of a conveyer for said sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, means for feeding a sheet of fabric to and superposing the same upon said bindin material, and means for distributing said fluent binder in the form of a substantially uniform film'between said sheets, said means comprising a rotary brush upon said binding material, and means for distributing said fluent binder between said sheets, said means com rising a rotary brush operative to exert a rushing eflect under pressure on said superposed sheet in a relative direction with respect to the sheet material having components opposite to and transmaterial.

13. In apparatus for producing laminated sheet material, the combination of a" traveling conveyer for said sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, means for feeding a sheet of fabric 'to and superposing the same upon said binding material, and means for distributing said fluent binder between said sheets, said means comprising a pair of rotatable brushes cooperative with and exerting pressure on said super osed sheet and adapted to distribute said binder between and remove excess binder from said sheets, said brushes being mounted for rotation on axes disposed at an angle to each other and transverse to the direction of travel of said sheet.

14. In apparatus for producing laminated ing conveyer for said sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, means for feeding a sheet of'fabric to and superposing the same upon said binding material, a brush, and a rotatable shaft upon which said brush is mounted above said superposed sheet said brush being operative to exert a rotary brushing effect upon said sheet in a relative direction having components opposite to and transverse to the direction of, travel of said laminated sheet, said brush being removable from operative osition without removal of its operating s aft from its mounting. x

15. In apparatus for producing laminated sheet material, the combination of a longitudinally traveling conveyer for said sheet material, means for. supplying fluent binding material in a layer above a lower sheet of said laminated material, means for feeding a sheet of fabric to and superposing the same upon said layer of binding material, a rotatable shaft, and a brush mounted on said shaft above said superposed sheet and operative to exert a brushing effect uponsaid sheet in a direction having components opposite to and transverse to the direction of travel of said laminated sheet, said brush comprising a bristle-carrying support detachably secured in operative position on said shaft.

16. In apparatus for producing laminated sheet material, the combination of a longitudinally traveling conveyer for said sheet material, means for supplying fluent binding material in a layer above a lower sheet of said laminated material, means for feeding a sheet of fabric to and superposing the same upon said layer of binding material, a rotatable shaft, and a brush mounted on said shaft above said superposed sheet and operative to exert a brushing effect under pressure upon said sheet in a direction having components opposite to and transverse to the direction of sheet material, the combination of a travel-.

. maasos travel of said laminated sheet, said brush comprising a longitudinally split bristle-canrying support de achably secured in operative position on said shaft, the bristles on said support being arranged in a plurality of rial, means for depositing fluent bindingmaterialon the layer of mica flakes disposed'on a ing the same upon said binding material, ro-

tary means for distributing said fluent binder between said sheets and about said mica flakes, said rotaryc means being engageable with the upper surface of said second sheet of fabric, and means for subjecting said laminated sheet material to a heating and drying operation subsequent to said'distributing operation,

said latter means comprising an enclosure through which said laminated material is conveyed, and means for supplying heat to said enclosure during the travel-of said-laminated material therethrough.

18. In apparatus for producing laminated sheet material, the combination of a -longitudinally traveling conveyer for said sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, means for feeding a sheet of fabric to and superposing the same upon said bindtween said sheets, said rotary means being engageable with the upper surface of said second sheet of fabric, and means for subjecting said laminated sheet material to a heating and drying operation subsequent to said distributing operation, said means comprising an enclosure through which said laminatedmaterial is conveyed, means for supplying heat to said enclosure during the travel of the sheet material therethrough, and means for circulating air about said laminated material with a discharge conduit adjacent the forward edge of the enclosure for drawing off the products of the drying of said sheet material.

19. In apparatus for producing laminated sheet material, the combination of a traveling conveyer for said sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, means for feeding a sheet of fabricto and superposing the same upon said binding material,-

means operative upon said superposed sheet for distributing said fluent binder in the form of a film between said sheets, means for sub for saidsheet material outside of saiddrying enclosure, and means for driving said roll to produce a substantially constant linear speed of the sheet material beingwound thereon.

- 20. In apparatus for; roducing laminated sheet material, the com ination ofa longitudinally-tra've ingconveyer for said sheet material, means for supplying fluent bindin' 0 material above a lower sheetof saidlaminated material, means for feeding a sheet of fabric.

to and superposing the same upon said binding materia means operative 'upon said said laminated sheet materialto a heating superposed sheet for distributing said fluent -lower sheet of said laminated material, means for feeding a sheet of fabric to and superposand drying operation subsequent to said distributing operation, a collectin roll for said sheet material outside of-said rying' enclosure, and'mean's for driving said rollto produce' a substantiall constant'linear speed of Y the sheet material; eing wound thereon, said means comprising a slip clutch in'the driving connection to said collecting roll.

21. In apparatus for producin sheet material, the combination of atravelin-g conveyer for said sheet material, means for supplying fluent binding material above a laminated lower sheet of'said laminated material, means for feeding a sheet of fabric to and superposing the same upon said binding material, means operative upon said superposed sheet for distributing saidfluent binder in the form of a film'between .said sheets-of fabric, andmeansfor subjecting said. laminated sheet material to a heating and drying operation subsequent to the distribution of binder therein, acol'lecting roll for said sheet material 'outside of said dryingv enclosure, and

means for driving said roll to produce a sub-' stantially constant linear speed of the sheet material being wound thereon, said means comprising a device for applying a variable frictional holding effect upon said sheet material, and a slip clutch in the driving connection to said-collecting roll.

22. In apparatus for producing laminated sheet material, the combination 'of' a traveling conveyer for said sheet material, means for supplying fluent binding material above a lower sheet of said laminated material, and means for feeding a sheet of fabric to and superposing the same upon said binding masaid laminated material, and means for feedto the normal position of said active roll on exhaustion of said active roll, said means comprising angularly spaced and pivotally mounted pairs of supports each adapted to receive and hold a roll of said fabric, the arrangement being such as to permit mounting of a reserve roll of said fabric in one pair of arms while the active roll mounted in the other pair of arms is supplying fabric to the apparatus.

24. In apparatus for producing laminated sheet material embodying a layer of mica flakes in overlapping relation and originally fluent binding material therefor between a plurality of sheets of fabric, the combination of a longitudinally traveling conveyer for said sheet material, means for depositing fluent blnding material on the layer of nnca flakes disposed on a lower sheet of said laminated material upon said conveyer, means for feeding a second sheet of fabric to and superposing the same upon said binding material, means for distributing said fluent binder in the form of a film between said sheets of fabric and about said mica flakes, said means comprising a rotatable brushing device cooperative with and exerting pressure on said superposed sheet and adapted to distribute the binder between said sheets and remove excess binder therefrom, means for subjecting said laminated sheet to a heating and drying operation subsequent to said distribution of the binder, a take-uproll outside of said drying enclosure, and meansfor driving said conveyer, said brushing device and said takeup roll to cause the contlnuous production of finished laminated sheet material and the colport, superposing a second sheet of fabric upon said binding material, and distributing the fluent binding material by brushing the exposed surface-of said second sheet during its travel and in a direction having components transverse to and opposite to the direction of travel ofsaid laminated sheet ma terial. i

26. The method of manufacturing laminated sheet, material, whichcomprises depositing a fluent binding material. above a sheet of fabric carried by a support, the amount of saidbinding material being in excess of that required for final binding purposes, superposing a second sheet of fabric upon said binding material, and distributing said binding material and removing the excess thereof by continuously brushing the exposed surface of said sheet material without further application of binding material thereto and in a direction having components transverse to and in line. with the edge of said sheet material.

27. The method of manufacturing laminated sheet mica, which comprises depositing a. layer of mica flakes in overlapping relation upon a sheet of fabric carried by a support, depositing a layer of fluent binding material upon said mica flakes, the amount of said binding material being in excess of that required for binding purposes, superposing a second sheet of fabric upon said mica flakes and binding material thereon, and distributing said binding material and removing the excess thereof by brushing the exposed surface of said sheet material in a direction having components transverse to and in line with the edge of said sheet material.

28. The method of manufacturing laminated sheet mica, which comprises depositing a layer of mica flakes in overla ping relation upon a sheet of fabric carried y a traveling support, depositing a layer of fluent binding material upon said mica flakes during travel thereof, the amount of said binding material being in excess of that required for binding purposes, superposing a second sheet of fabric upon said mica flakes and binding material thereon, and distributing said binding material and removing the excess thereof during travel of said sheet by brushing the exposed surface of said sheet material in a direction having components transverse to and opposite to tlahe direction of-travel of said sheet materia 29. The" method of manufacturing laminated sheet material, which comprises depositing a fluent insulating binding material above a longitudinally traveling sheet of fabric, superposing a second sheet of fabric upon said binding material, and distributing the fluent binding material and'smoothing the laminated sheet material during its travel by brushing the exposed surface of said second sheet in adirection having components opposite to and transverse to the direction of travel of said laminated sheet material, and finally heating and drying said laminated sheet material to cause said binding material to harden and to cement the sheets of said laminated material. v

30. The method of manufacturing laminated sheet material, which comprises depositing a sheet of fabric on a longitudinally traveling support, depositing a fluent insulating binding material above said sheet of fabric, superposing a second sheet of fabric upon said binding material, and distributing the fluent binding material and smoothing the laminated sheet material during its travel by continuously brushing the exposed surface of said second sheet in different directions from an intermediate point of the sheet material, said directions each having components transverse to and opposite to the direction of travel of the laminated sheet material.

31. The method of manufacturing laminated sheet insulating material, which comprises depositing a layer of mica flakes in overlapping relation on a sheet of fabric carried by a traveling support, depositing a fluent insulating binding material upon said layer of mica flakes, superposing a second sheet of fabric upon said binding material, and distributing said binding material and smoothing the laminated sheet material during its travel by continuously brushing the exposed surface of said second sheet of fabric in different directions from an intermediate point of the sheet material, said directions each having components transverse to and opposite to the direction of travel of the sheet material.

32. The method of manufacturing laminated sheet insulating material, which comprises depositing a layer of mica flakes in overlapping relation on a sheet of fabric carried by a traveling support, depositing a fluent insulating binding material upon said mica flakes, superposing a second sheet of fabric upon said binding material, and distributing said binding material and smoothing the laminated sheet material during its travel by brushing the exposed surface of said second sheet in a direction having components opposite to and transverse to the direction of travel of said sheet material. v

33. The method of manufacturing laminated sheet insulating material, which comprices depositing a layer of mica flakes in overlapping relation on a sheet of fabric carried by a traveling support, depositing a fluent insulating binding material upon said layer of mica flakes, superposing a second sheet of fabric upon said binding material, and distributing said binding material during travel of said sheet material by a stroking operation on the exposed surface of said second sheet in a direction having components trans verse to and opposite to the direction of travel of the laminated sheet, and subsequently drying said laminated sheet material during its travel Within an enclosure wherein it is subjected to a current of air which removes and conducts away products of drying.

34. The method of manufacturing laminated sheet insulating material, which comprises depositing a layer of mica flakes in overlapping relation on a sheet of fabric carried by a traveling support, depositing a fluent insulating binding material upon said layer of mica flakes, superposing a second sheet of fabric upon said binding material, distributing said binding material and smoothing the laminated sheet material during its travel by continuously brushing the exposed surface of said second sheet in a direction having components opposite to and 

